The present invention relates to a novel and useful temperature indicating device.
Temperature indicators are extremely helpful in determining whether extremes of temperature have been exceeded in certain environments. It is often desirable that such indicators operate automatically and maintain a signal indicating that a temperature extreme has been exceeded long after this has occurred. In other words, would be a simple matter to have an operator periodically check such temperature indicators, rather continually checking the same or continuously monitoring the same, which can be a very expensive system.
U.S. Pat. Nos. 3,290,942, 3,622,932, 3,947,758, and 4,064,827 show temperature indicating devices in which a bimetallic element, which may be a disc, bring an indicator into view for alerting the fact that a temperature level has been reached.
U.S. Pat. No. 4,091,763 shows a temperature indicator in which a bimetallic disc is snapped into view when it passes through an opaque fluid to indicate a temperature level or extreme.
U.S. Pat. No. 5,076,197 shows a temperature indicating device in which a bimetallic disc is itself moved from a chamber and into contact with an indicator by a spring when the disc inverts.
A temperature indicator which quickly and simply signals the exceeding of the temperature extreme would be a notable advance in any industrial process where temperature is a key parameter.
In accordance with the present invention a novel and useful temperature indicating device is herein provided.
The temperature indicating device of the present invention utilizes a housing which is formed with an interior and exterior portion. The interior includes a first chamber and an adjacent second chamber which communicates with the first chamber. An opening is also provided through the housing to communicate the exterior of the housing to the interior of the housing.
A bimetallic element is also employed in the present invention and is capable of assuming a first configuration and a second configuration upon a certain change in temperature. In a particular embodiment, the bimetallic element may take the form of a disc which inverts by a snapping action from a concave to a convex configuration. Of course other bimetallic element configurations may be employed in the present invention in this regard.
A movable member is also found in the present invention and is located in the first chamber. The movable member contacts the bimetallic element while the bimetallic element assumed its first configuration prior to any temperature change. At this point, the housing also includes a wall portion which bears on the bimetallic element in the second chamber while the bimetallic element is in its second configuration. The movable member is provided with a first end portion and a second end portion, in this regard. The first end portion of the movable member contacts the bimetallic element while the second end portion of the movable member contacts spring means. The movable member may also be formed to lie in a channel within the housing which guides the movable member by the urging of the spring means. Such motion takes place when the bimetallic element assumes its second configuration, which in the case of a disc generally makes the form of an inversion of the disc. At that time, the spring means urges the movable member into relative movement between itself and the bimetallic element. The spring means may also be guided in its urging motion. In certain cases, the channel utilized for guiding the movable member may also be employed to guide the spring means.
Signal means is also found in the present invention for indicating the relative movement between the movable member and the bimetallic element. The signal means utilizes the opening which connects the exterior of the housing to the interior of the housing. A surface within the first chamber is generally aligned with the opening, but is obscured by the movable member when the bimetallic element has assumed its first configuration. Upon the assumption of the bimetallic element""s second configuration, the movable member passes away from the surface and allows the surface to be viewed through the opening in the housing. Of course, the surface may be marked or colored to heighten its visibility to the user.
It may be apparent that a novel and useful temperature indicating device has been described.
It is therefore an object of the present invention to provide a temperature indicating device which is reliable and simple to operate and may be employed in remote locations.
Another object of the present invention is to provide a temperature indicating device which indicates the exceeding of an extreme of temperature and maintains that indication, although the system may again pass below both such temperature extreme.
A further object of the present invention is to provide a temperature indicating device which is relatively inexpensive to manufacture and may be reset easily after the temperature indicating device has been triggered by an extreme of temperature.
Yet another object of the present invention is to provide a temperature indicating device which includes a minimum of moving parts and is quite reliable in its operation.
The invention possesses other objects and advantages especially as concerns particular characteristics and features thereof which will become apparent as the specification continues.